Multi-family / Apartment classification

[Clay W.]

I would like to find out a more specific definition / classification of what exactly constitutes a multi-family dwelling.

The terms dup-lex, trip-lex, quad-plex, 5-unit +, apartments, etc. seem to wear many different coats.

For example, I would see a building like this and when I search on the county's zoning map it would be defined along the lines of a "low-rise" apartment:

I see many small units combined into one single building with various access points.

However, I also see other locations / neighborhoods that are filled with only SFR's and straight-forward duplexes. I look at the zoning map and the lots for these properties will stipulate that they are classified as "single-family residences" *6-8 units per acre. *I don't know if this means that one could develop 6-8 units on a parcel that would other have a SFR on it*

Then, I have seen parcels in the same neighborhoods that were developed many years ago and they will have multiple single-level "cottage"-like 1 bd/1 ba rentals on one lot (*all detached). There might be six + units on one lot yet the parcel definition will say "single-family residence" as well.

So would these also be considered multi-family? Do multi-family units/ parcels / zones mean that units must be somehow attached?

~Clayton